Method of making yarns



Patented Oct. 27, 1953 METHOD OF MAKING YARNS Anton F. Burkardt, New York, N. Y., assignor to Sativa Corporation, a corporation of New Jersey No Drawing. Application February 28, 1950,

Serial No. 146,917

4 Claims. 1

This invention relates to a method of making yarns and has for its object the manufacture of improved yarns and fabrics by balancing the Wet and dry strength of yarns and fabrics.

It is known that most yarns and fabrics and especially those made of synthetic fibres or wool lose from 25 to 65 per cent of their strength when put into cold or boiling water such as occurs when washing.

It is also known that because of this condition fabrics often suffer more from washing than from wear.

By the present method the above conditions are improved or overcome by blending various fibres having differing characteristics which, when blended, bring about a stabilization or a balance of yarn strength under wet and dry conditions, producing washable yarns superior to those heretofore known.

I have discovered that natural bast fibres such as hemp, flax or ramie, when degummed and processed as described in my copending application, Serial No. 103,262, filed July 6, 1949, increase in strength up to 100% in cold water and up to 150% in boiling water. Such fibres so treated are hereinafter termed Sativa, the common trade name by which they are commercially known, but any other suitable bast fibres can be used.

The aforesaid application Serial Number 103,262 discloses a method and apparatus for producing bast fibers of various natural staple lengths without cutting or chopping the fibers in any manner in order to separate them into short lengths. Such chopping or cutting leaves the fibers with sharp cut edges (not tapering ends like the natural fibers) and makes them difiicult to spin over standard cotton machinery. This application, therefore, contemplates the use only of bast fibers of natural staple length. How these fibers are degummed and preshrunk is immaterial to the practice of this invention where the inventive concept resides in the employment of such fibers of natural staple length having a natural axial twist in one direction combined with another fiber having a natural axial twist in the opposite direction.

By blending fibers treated as above, or other suitable bast fibers with other fibers such as wool, cotton or synthetic fibres such as nylon, rayon or Aralac, said other fibres being known to weaken when Wet, I have produced yarns having the same wet or dry strength or yarns that are stronger wet than dry.

I also refer to my co-pending application, Serial Number 130,933, filed December 3, 1949, of which the instant application is a continuation-in-part, which refers to the shrink-control Normal Wet Hot Wet,

316 lbs. 510 lbs. 726 lbs.

% increase normal to hot A 7/1 Sativa yarn Normal Wet Hot Wet 139. 5 lbs. 288 lbs. 328 lbs.

% increase normal to hot Such yarns may be used to stabilize the wet and dry strength of fabrics as hereinafter referred to.

As a basis of comparison the following table gives the normal and wet strength of typical rayon, Aralac (synthetic fibre made from casein) woolen and cotton yarns:

Normal, Wet.

5. lbs.

Bright Tow Rayon, 18/1 96 35 Spun Rayon, 18/1. 116 44 Spun Rayon, l2/l 159 62 Aralac, 18/1 35 14 Aralac, 12/1 67 26 Wool, l l 97 78 Cotton, 12/1 .i 159 174 It will be observed that the wet strength of cotton is somewhat higher than the dry strength thereof but not suflicient with which to practice the method herein disclosed; that is to say, cotton cannot be used instead of S'ativa or other bast fibres for blending to stabilize the wet and dry strength of yarns and fabrics. With cotton there is not enough variation between dry and wet strength, and the wet strength is seldom more than 8 to 10% stronger than dry.

The variation of bast fibres may be, as herein stated, over 100%. That is, the increase in strength when wet may be 100% more than when dry. This enables the herein disclosed method to be practiced, and a large number of different blends can be made of almost any relative wet or U dry strength.

examples of blends of bast fibres with other fibres to produce yarns by the instant method.

YARN TENSILE STRENGTH 120 Yard Skein It will be understood that the figures given herein are by way of example and may vary with different yarn counts and batches of materials and even with skeins. in the same batch. Therefore it is impossible to give exact figures for each blend listed herein and some experimentation with selected materials is necessary. The experimentation, however, is not to discover what is herein disclosed or in order to practice this method to determine if the method is workable, but is solely for the purpose of adapting this method to the particular size of yarn and ma- Sam 1e Dr Wei; Percentages by Welght lbs 7 12/1 35%N on: 128.0 30% Bright. Tow Rayon. {65% Sativa s 12/1 0 35% Nylon 111.2 119. c

30% Bright Tow Rayon-.-"

Sam is Dry, Wet,

N01? Percentages by Weight lbs.

657 Sativa 9 12/1 {35% Nylon and Wool 0 4 10 12/1 114.4 121.4 11 12/1 am 88. 8

18 8/1 218.4 19 8/1 l 234.0 20 s 1 {as% Nylon? 214.4 lSBright Tow Rayon. 65 a iva 21 8/1 2 M3180 84.4 124.6

It will at once be apparent from the above table that by varying the percentages of the various fibres used, that the relative dry or wet strength can be varied within wide limits.

Referring to sample #1, if the nylon-Sativa content is reduced to and the rayon increased to 50%, the resultant dry strength will remain at 55.2 lbs., and the wet strength will be reduced to 35 lbs.

Referring to sample #16, if the Sativa is reduced to 25% and the wool increased to 75%, the resultant dry strength will be approximately 51.2 lbs, and 52.3 lbs. wet. If. 15% Sativa is used with 85% Wool, the dry strength is approximately 50.1 lbs. and the wet strength 42.1 lbs.

It will be observed that in some cases the dry strength is greater than the wet strength and that in others the wet strength is greatest. It is therefore evident that by proper blending of Sativa with other fibres, practically any relative wet or dry strength can be attained.

Sativa, nylon and bright tow rayon, the following formula may be used.

t 's. where:

R=ratio of wet strength to dry strength of combined yarn percent Sativa percent nylon X 1 00 percent rayon Other similar formulas may be used to compute the percentage of diiierent .fibres to be used in combination, and the development of such formulas will be evident from the example given above.

It will be understood that the various fibres employed are blended in any suitable manner. made into rovings and spun as usual on textile machinery now in common use, no special machinery being required.

Yarn having been made as just described, it may be used either alone or mixed with other yarns composed wholly of cotton, wool or other fibres or a mixture of such fibre to produce a fabric having the wet and dry strength resulting from the yarns used therein.

For example, a fabric made of the yarn described in sample #1 above, will have the relative wet and dry strength given for that yarn. Thus a fabric can be produced which, when laundered, will maintain its normal dry strength; or fabrics can be made that will be stronger wet than dry.

What is claimed is:

1. The method of making a composite yarn having predetermined wet and dry strengths including the step of determining the relative wet and dry strength of Sativa produced from degummed preshrunk bast fibers of natural staple length; the step of determining the relative wet and dry strength of other fibers; the step of combining all said fibers by weight in accordance with the following formula:

tel-mined relative wet and dry strength differing from the normal wet and dry strength of the component fibers thereof which comprises the step of degumming and preshrinking bast fibers; the step of determining the wet and dry strength of said fibers; the step of selecting another fiber and determining the wet and dry strength thereof the step of combining said fibers; and the step of spinning all said fibers together to form the composite yarn aforesaid, said first fibers being of natural staple length when so spun.

3. The hereindescribed method of producing a composite yarn in which the wet and dry strengths approach each other in value, which includes the step of degumming and preshrinking bast fibers, said bast fibers having a wet strength greater than the dry strength thereof;

percent nylon percent Sativa 100 percent rayon and the step of spinning said fibers together to produce said composite yarn aforesaid.

2. A method of making yarns having a predethe step of selecting a predetermined quantity of said fibers; selecting a second predetermined quantity of fibers having a wet strength less than the dry strength thereof; and the step of spinning all said fibers together to produce the composite yarn aforesaid, said first fibers being of natural staple length when so spun.

4. The hereindescribed method of producing a composite yarn in which the wet and dry strengths approach each other in value, which includes the step of degumming and preshrinking bast fibers, said bast fibers having a wet strength greater than the dry strength thereof; the step of selecting a predetermined quantity of said fibers; the step of selecting a second predetermined quantity of fibers; and the step of spinning all said fibers together to produce the composite yarn aforesaid, said bast fibers being of natural staple length when so spun.

ANTON F. BURKARDT.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,165,758 Milson July 11, 1939 FOREIGN PATENTS Number Country Date 380,270 France Oct. 3, 1907 

